Purifying gases of dry distillation and recovering the by-products thereof.



K. BURKHEISER.

PURIFYING GASES 0F DRY DISTILLATION ANDI R'ECOV ERING THE BY-PRODUCTSTHEREOF. APPLICATION FILED AueJ. 1912.

1 1 60,836. Patgnted NQV. 16, 1915.

v WA-SH 1.76

FILTER P175615 SS I v sus susmu E F, 2 u a 5, U

loll l LARL BURKHEISER, OF EAMBUBG, GERMAN 3. ASSIGIIGR 'EQ BURKEEZSEE &(QGEIPAHE (GESELLSCHAFT IEIT IBESCHBANXTE HAFTUNG}, 01 HAI'EB'UBG, ii(303..-

PURIFCEING GASES G DRY DISTILLATION AND BECOVEBENG BY-PESFJUCTS TEEREDF.

4 cense.

Specification of Letters Patent.

Patented El l6,

Application filed August 7, 1912. Serial I50. 713,759.

T 0 all whom it may concern it known that 1, line Bonnnnisnn, a subjectof the Emperor of Germany, residin; in the city of Hamburg, Empire ofGermany, have invented certain new and useful Improvements in PurifyingGases of Dry Distillation and Recovering the By- Products Thereof; and Ido hereby declare the following to be a full, clear, and exactdescription of the invention, such as will.

enable others skilled in the art to which it appertains to make and usethe some.

The. methods heretofore customary in practice for the purification ofthe gases of coal distillation hy' the removal of sulfureted hydrogentherefrom have consisted almost without exception in passing the gasesover lime or over an. artificial or natu ral body of hydrated iron oxid,after the gases have been freed from tar and ammonia. This manner ofpurifying the 'gases from sultureted hydrogen requires exceedinglyextensive purifying. devices on account of the extraordinary slowness ofreaction of the materials employed under the usual con ditionsprevailing. The method known as the Burlrheiser method, whereby thecapacity for reaction or the purifying mass employed as increased by apreliminary treatment of the irass, involved an advance over the priorstate of the art in this direction. Nevertheless, all of these methodsoi purifying, including the preparatory treat- .ment of the mass, relateto so-called dry purification, Whereas vvet purification has always beenregarded as the ideal method for gas purifying. and many inventors andothers skilled in the art hrweatternpted to devise a practicallyutilizable method of that type; So as I am aware, none of these effortshave heretofore been sufiiciently acceptable to find permanentacceptance in practice.

The seemingly obvious. method of Wetpurilication is the Washing of gasesby a metal salt solution. I Experiments in this-direction, however,proved unavailing 'hecause' the metal salt solution was either dificiiltto ,regenerate or could not be regenerated at all,

for which reason these methods were economically unsatisfactory. Forinstance, the very interesting method or" Claus may be referred to inthis connection, wherein the gases Were Washed with a solution of NH andthe absorbed CO and l-LS were thereafter driven off by cautious heatingto some What over 90 (1., and the residual NH, solution was used anewfor the washing of the gases. lt'was found not feasible to employ thismethodin practice, because the carbon dioxid (which was always presentin large quantity and which drives the sulfureted hydroen out of thesolution,) made it necessary to maintain more ammoni" 'n thecirculationthan was necessary for znoination and consequently very largequantities of liquid had to be heated and cooled. it has alsooeenproposed to wash the gas With liquid containing, in suspension,"hydrated iron oxid or bog iron ore. This method, however, failed becausehydrated iron oxid reacts much too slowly in the absence or a suiiicientquantity of alkali.

' The present invention contemplates freeing the gas from sulfuretedhydrogen by utilizing the great aihnity of the allralis for sulfuretedhydrogen, to remove the latter ii 0111 the gas, and, furthermore,contemplates the regenerating of the alkaline sulfids so produced, bytreating them with hydrated iron oxid, 'Bymeans of this combination. is

made possible to expedite the naturally slow reaction between sulfuretedhydrogen and hydrated iron oxid, even in the wet process, to such anextent that the gas purification can be carried out in an extremelysmall space.

ln the practice of the invention, the gas is treated in a suitableWasher With an alkaline solution, and then the alkaline sulfids soproduced are deprived of their sulfur by a wash liquid, containing, insuspension, hydrated iron oxid, so that the alkaline solution can beutilized anew for the purification-of the gases from sulfuret'edhydrogen.- A particular embodiment or" this method, which is especiallyfeasible on account of the large quantity of carbon dioxid often presentin the gases or coal distillation, consists in simultaneously supplyingto the Washer with because,

. is sin'uiltaneouslythe alkaline solution the hydrated iron oxid, sothat, the re enerating of the alkaline soluticu proc tion lllCUll'lcrlconstantly anew incondition to washout sulfureted hydrogen. T hesatuiated iron sulfur compounds are removed from thc alkaline solutionby filtration, decanting, or the like, and the filtrate with a freshquantity of the hydrated iron oXid is employed anew for the washing.

llhe invention extends furtlna to the em ployment oi the ammonia.contained in the gas itseli instcadof a separate alkali, by ha ring theremoval of the sulfureted hydrofollow immediately upon the removal ofthe tar, r'. 0., the sulfureted hydrogen purification is undertakenwhile the gas still contains its ammonia. The employment of spe al allnii in such case is superfluous, as noted, the ammonia contained in thegas serves as such/ Qt course, in this method oi. sulfureted hydrogenpurification, as soon the washing liquid is saturatei'fl with hi furtherwashing out of the ammonia by the washing liquid does not take place.'ihis' mode of operation has the special advantage that all. of thediiiiculties incident to sulfuretcd hydrogen in the recovery oi ammoniadisappear, and the am- :ionia, as such or 2.5 sultite or sulfate of armmoni be recovered from the gas direct- .st'coniilition. Heretofore, in

" ofconcentr ted ammonia water men .un sulfate by of foreign uricacid,the sulfa ogen is able to reduce the sulfuric rlurous acre abovedescribed inetlirc lGiUl'l n purification, tl: anogeu con r unless spe:meast, will take up ydrz-itcd ir oxid by the uhle iron-c iogen comcmuplcte i e 'g'cncration e purifying mass ion: dillicull. The inventionthereilcmpiates avoiding the production nub-l0 iron-cyanid coiupounds byadd-- ing to the alkaline solution some sulfur or some oi the masscontaining sulfur, or by 'ith the a quantity of air or r this means, allof the cyanogen and completely absorbed, because alkaline polysulfidscan form and all oi the \'anogen is converted into the correlingallrali-sulio-cyanogcn compounds. lna, nuch as these compounds arereadily soluble, they can be readily separated from the iron-saliiurcon'mounds and can be subiectedio a special treatment. The treat ment ofthese, sulio-cyanogen compounds is especially feasible from a commercialstandof sul'iu- I point if. they can be converted into a subat once andso that the 'solustance which is already present in the coaldistillation gases and if they can be recovered as a valuableby-product. The recorery of by-products would in such case be simplerand would be particularly manifested in an increase in theoutput of theone valuable by-prodmrt.

A further object of the invention con sists, therefore, in increasingthe output of ammonia by converting the sulfocyanogen con'ipounds thusobtained into ammonia, and carrying along and treating further the saidammonia together with the ammonia otherwise present in the gases. sodoing, not only is the sulto-cyanogen product (which is in itselfunwelcome) removed. and in its stead the valuable ammonia contained inthe gas recovered, but the additional important advantage is attained,oi enriching the gas further with ammonia. i

l s hereinbe'l'ore explained, the ammonia serves as an in ermediary forthe reaction between the sulfurcted hydrogen and the hydrated iron oxid;2'. 0., the more ammonia is present in the gas, the more readilyandreliably will. the absorption of the sulfuretcd hydrogen go on. Theconversion of the sulfo-cyanogen compounds into ammonia, may, therefore,with particular commercial advantage, be brought within the scope of drydistillation or gasification, in .vicw of the hereinafter reciteddiscoveries made by me, by charging the sulfo-cyanogen compounds,together with the coal, into the dis tilling furnaces or gasifyiugfurnaces. These discoveries or observations nvolve the attainment of thefact that when sult'ocyanid compounds are treated at a high temperaturewith substances which at such tem- "ierature give off hydrogen or water,the .ulidcyanid is converted into ammonia. In he dry distillation ofcoal or similar substances. all of the prerequisites for such aconversion are present, and the practical. carrying out of the processhas also establishcd the correctness of these observations. Accordingly.the conversion of the cyanid into ammonia is practised within the rangeof distilling processes or gasifying processes ing process the mass thusfreed from sulfur and therefore again receptive, and using it 101'regenerating the absorption liquid. In

moose-c a 3 lio l was en Water has emmind This anipmnp' to an ilc Wshing s dclire and r The er. which t i i a IGSOIQULOQ o1 v cidamnionium' o in HE; during the scrubber and formed;

reign i 5 and iorth.

1 in otion includes a simplification oi method by utilizing as the old amixture of acid and normal common elevated receptacle to the scruhher asWQll to the SO scrubber collected from this apparatus in a ringreceptacle. This Wash in condition -5-1: take up 3G 51 i plied forapparatus.

vone pump is used in this method.

in sullite which mixture is supplied and during the passage scrubber thenormal sulfite' an se as Well as through the 1e li e again collecting inthe common bring receptacle and coming from H1099 nbher and the SOscrubber consists therefore of a mixture of acid and normal ammoniumsuliite, and is therefore again adapted absorb S(). as Well as K11 andto serve for sprinkling: the beforementioned 5 Instead of severalelevated receptacles and low-lying receptacles and'thc correspondingnumber of pumps for consaying the Wash liquid only one elevatedreceptacle and one low-lying receptacle and 0 The method is thereforematerially simplified in its apparatus and its manipulation. In thisprocess, therefore, the wash liquid cont-inn- 1 becomes richer in normalammonium 1 5 ,be taken that while realizing the most complete absorptionpossible or the ammonia, the salt cahe removed in a suitableinanner.

A inrther object. of the invention consists in the separation of theammonia from the cases of the dry distillation or gasification in twostages, 0., first in a saturator 5 Where the formation of he salt takesplace by absorption of the greater part of the aninionizu and then in ascrubber Where the. reniai'nc ci' the ammonia is Washed out. Both ofthese apparatus, saturator and ammonia scrubber, are supplied irom thesame elevated receptacle with the Wash Water consisting'of acid andnormal ammonium sailfitev The gas which first passes through thesaturator with its entire quad tity of ammonia, gives up the greaterpart of its ammonia therein, so that necessarily .dae salt precipitationmust take place in this apparatus. To the ammonia scrubber there thenpassesonly a smaller part of the ammonia contained in the gases, so thatin the ammonia scrubber only a moderate enrichment of the wash liquidwith normal ammonium sulfite takes place and a precipitation of salt cannever occur in this washer. There'lorethe washing out of the ammonia iscomplete under all conditions because only a part of the capacity of thewash liquid introduced into the ammonia scrubber is put underrequisition. Furthermore, by the absolute restriction of the saltprecipitation to the saturator, all obstruction of the ammonia washer bythe formation of salt is avoided.

rt mode'of operation which has shown itself feasible in practice willnow be described, with reference to the accom 'ianying diagrammaticdrawing.

The gas produced in the furnace 1 passes through the hydraulic main 2and conduit 3 into the cooler l, and is cooled therein.

The ammoniawater separating out in the cooler is treated in the(llStllllIU column 5' and distilled back again into the gas, so thatupon its exit from the cooler all of the NH is again contained in thegas, The gas exhauster 6 sucks the gas and forces it through the tarseparator 7 where the last traces of tar are removed. Thence the gasentersthe sulfureted hydrogen purifier 8 which ishere assumed to be arotating purifier of the cyanogen washer type. The wash liquid with thesuspended hydrated iron oxid mass is pumped counter-wise to the gas fromchamber to chamber, so that in the last chamber, 2'. c., in the chamberin which the gas containing H 3 enters, the mass is nearly saturatedwith ILS and the wash liquid is at its richest in sulfo-cyanidcompounds. By the pipe 9 and pump 1.0, the mass'in suspension of thislast chamber is forced to the filter press 11 where a separation of themass from the liquid takes place. A part of the liquid is pumped by thepipe 15 to the coal bunker 16, moistens the coal somewhat and enterswith it into the re tort bench 1, where a conversion of thesulfocyanogen compounds into ammonia takes place. which'ammonia goesover into thc'gas. The conversion of the sulfo-cyanogen compounds intoammonia can also, of course, take place in separate receptacles anddevices in accordance withwhat has been hereinbefore stated. Theremaining part of the liquid pressed out and the water employed forwashing of the filter cake flows through the conduit 14- into the vessel12 provided with a'stirring apparatus. The filter cake passes throughthe hopper 17 into the regenerator 13 where the revivification of themass by air takes place up to the formation of sulfur dioxid or sulfurt-rioxid :and this revivification up to the formation it sulfur dionidor sulfur trioxid been said hereinbefore, the heating can be carried sofar beyond the roasting process proper that any iron sulfate compoundspresent which would prejudice the capacity of the mass for furtherabsorption are removed. The mass revivified leaves the regenerator bythe chute 1S, falls into the receptacle 12 and together with the pressedout wash liquid is pumped back again to the rotating purifier 8 where itagain venters the cycle. The SO produced in the regenerator' l3 iswashed out in the air scrubber 19 and the NH, contained in the gas iswashed out in the saturator 20 and ammonia washer 21. The salt producedis separated from the mother lye in the centrifugal separator 22.

Having thus described my invention, what I claim is 1. The method ofpurifying gases of dry distillation or gasitication with theSimultaneous recovery of the by-products, which consists in removing thesulfuretetl hydrogen froin the gases by an alkaline solution, andregenerating the alkaline solution by hydrated iron OXld; substantiallyas described.

2. The method of purifying gases of dry distillation or gasificationwith the simultaneous recovery of the by-products, which consists inremoving the sulfureted hydrogen from the gases by an alkaline solution,and regenerating the alkaline solution by hydrated iron oxid, theabsorption and regeneration taking place simultaneously; sub.-stantially as described.

3. The method of purifying gases of dry distillation or gasificationwith the simultaneous recovery of the lay-products, which consists inremoving the sulfureted hydrogen from the gases by'an alkaline solution,and regenerating the alkaline solution by hydrated iron oxid, theammonia contained in the gas being employed as the alkali; substantiallyas described. i

,4. The method of purifying gases of dry distillation or gasificationwith the simultaneous recovery of the hy-products, which hydrated ironoxid, the ammonia contained in the gas being employed as the alkali, enesubsequently freeing the gases fromam- I monia; substantially asdescribed.

5. The method of pnritylng gases of dry distillation or gasification,which consists in removing the sulfnreted hydrogen by an alkalinesolutiom converting the sulfur into S0 or $0 and employing it forbinding the ammonia contained in the gas,and regenerating the alkalinesolution by hydrated iron oxid {substantially as described.

5. The method of purifying gases of dry distillation or gasification,which consists in removing the sulfureted hydrogen by an alkalinesolution and-regenerating the alkaline solution by hydrated iron oxid, aportion of the alkaline solution being" convertremoving the snlfareted'hydrogen'hy an alkaline solution and regenerating the alltalinesolution by hydrated iron oXid',-.a portion of the alkaline solutionbeing converted into alkaline polysulfid solution, converting thealeaime polysulfidsinto sulfo-cyanogen -comp(mods and convertingsthesultof-cyano gen compounds formed into ammonia; substantially asdescribed. i

alkaline solution and regenerating the 'alka-' line solutionby hydratediron'oxid,- a p'or- .40 into alkaline polysulfid solution, converting ftion oi-the alkaline solution being converted the .polysulfids intosnlfo-cyanogen compounds, and converting the sulfo-cyanogcn compoundsformed into ammonia, and commi'ngling the ammonia thus obtained with Themethod of bnrifying gases of dry; 5 "distillation 6r gasifieationgirhichconsists In, 1 removing the sulfureted hydrogen by an that alreadycontained in. the gases; substantially as described.

9. In the purificati- 'n of gases of dry distill'ation -.or.gasification, binding the ammonia of the gas and the vSO of the air bybrmging them intoicontact with a'washing liquid Whichcontainsboth normaland acid ammonium sulfite; substantially as described.v 10. In thepurification of gases of dry distillation or gas1fication, "binding theammonia of the gas and the S6, of the air'by;

bringing them into contmt with a washing. liquid iyhich contains bothnormal and acid;

ammonium snlfite to produce salt formation,

and thenremoving the remainder of the ammonia in a scrubber;substantially as described.

In testimony whereof I aflix my signature,

in presence oftwo witnesses. V

Witnesses:

,WOLDEMAK HAnrT, I HENRY HAsm KARL BURKHEISER.

